The NASA Mariner10 mission in the 1970's provided a snapshot of the Hermean environment with its three flybys [1]}. These observations showed the presence of a planetary magnetic field [2]} and of a structured plasma environment [3]}. In particular, Mariner10 was able to perform measurements of the core of the electron distribution function (in the range 13.4-687 eV) during most of its orbit inside the Hermean magnetosphere [4]}. However, Mariner10 was not able to observe ions due to a technical failure [5]}.
